Individual Cylinder EGT Testing

[phate]

Originally Posted by Ziggo I think you guys are seeing cylinder 1 backwards. If the hump was restricting flow, and it was not balanced by the tune, it would have less air, and more fuel, meaning richer AFRs and lower EGTs

I have to remind myself every time, lol.

Parts 2 & 3 coming up soon

[GODspeed7]

Originally Posted by Fatguy729 Damn this thread rocks... But keeps getting more and more WAY over my head LOL

I like to think that by me reading this thread, regardless of how much I really understand, makes me a better person both intellectually as well as spiritually. Sure I may not "comprehend" what's going on but I was one of the first subscribers to this thread so it gives me the right to bash new brownies! I love my crazy bullshit logic!


Sent from my iBro 5 using tapatalk, Bro!

[Lex]

The nagging question for me is how much can we attribute this temperature difference to the shape and runner length of the exhaust manifold. Even simply looking on the web for the "orange" manifolds it's clear that the manifold design lends to certain runners developing hotter spots than others.

[Dano]

Originally Posted by Ziggo I think you guys are seeing cylinder 1 backwards. If the hump was restricting flow, and it was not balanced by the tune, it would have less air, and more fuel, meaning richer AFRs and lower EGTs

word...and retarded timing will increase EGT...as in startup IGN timing which heats up the cats.

[Lex]

Because exhaust enters the manifold in pulses, what you will generally find is that at a place where the pulses converge (ie the collector) you will see higher EGTs than in individual runners. This can be visually seen above. In diesels where EGTs are more strictly monitored they monitor EGTs either at the collector or right after the turbine.

3 and 4 clearly have shorter paths to the collector than 1 and 2 meaning that the probes themselves are closer to the collector.

Further, longer runners have more mass to dissipate heat across before entering the collector than the shorter runner given that each exhaust pulse generates the same amount of heat energy and they are equally spaced in time (which they are).

Yet ... 1 and 2 showed the highest temperatures consistently.

[phate]

Alright, hopefully I didn't fuck up that thread separation. I removed a bunch of irrelevant posts and some things where people were just bitching at people

Parts 2 and 3 shortly.

[Haltech]

When I worked for Acura, I was told that for every 5* of timing added over the base timing, expect your EGTs to increase 100F. Long before wideband use, we used EGT probes and gas analyzers to determine lean conditions with gen1 Legends with the V6 as they had some fueling issues.

Keep in mind this is port injection, so I would expect cooler cylinder temps in direct inject engines.

I appreciate Clint doing this EGT testing.. We always assumed cyl 1 was the leanest but now we can confirm it.

[Mfinlay04]

Wouldn't it make sense that cylinder 1 is seeing more air as the totally pressure is highest when first entering the intake manifold? And as the first cylinder fills with air the pressure drops across the manifold so the each cylinder essentially gets less and less air??

Totally talking out of my ass, with limited knowledge but just trying to make send of the data



Sent from my Galaxy Nexus using Tapatalk 2

[phate]

Part 2 - Ignition Timing Changes

Same fuel (literally the same tank of fuel), same exact hardware setup.

Similar to before, I only wanted to change one parameter at a time and watch the effects on EGT's. I started with my .68l (9.99 AFR target) tune from the last round of testing, and made subsequent tunes which pulled 2° (per tune) across the entire rpm range. I had a total of 4 tunes: 0°, -2°, -4°, and -6° from the original curve.

I'm attaching a "master" file for this set of tunes, again. I'm also attaching the roll up files for each tune. In either case, you can find the individual runs, they just aren't in separate files. I've left the charts in each .xlsx file.

Overall, this is what each tune's load/ignition advance/afr curve looked like. I don't find anything else changing significantly between the runs. These runs were actually taken in very similar weather to the last set of runs (AFR change sets), so even ambient conditions aren't much different.



Here, I've broken out each tune's EGT data into separate runs, charted together.

Blue=Cylinder 1
Red=Cylinder 2
Green=Cylinder 3
Purple=Cylinder 4

For the sake of comparison to the initial set of runs on this tune, this is the .68l (target 9.99AFR) EGT data from the last set of runs (AFR changes - tune version 1.09_.68l):



This is the new version, which did not alter anything in the tune, except for the file name:
1.10_.68l_-0 (last two digits indicate timing pulled from original)

^^pretty similar, within 15°F or so

1.10_.68l_-2


1.10_.68l_-4


1.10_.68l_-6


This is what the EGT's look like, side by side, for each tune's runs:


And, for the sake of consistency, this is the ΔT between cylinder 1 and cylinders 3 & 4 for each run:






Sooo, what I've learned today:

• For every 2° of timing pulled, we increase EGT's by ~50°F (that's 25°F/1° timing, for the dense, lol)

^^Nothing else crazy showed up today, lol.







Part 3 - By-Cylinder Ignition Compensation Testing

So we have that sweet toggle in ATR for "Use Ignition Per Cyl. Comp."....but no one has had a proper rig to test this. The corresponding table *should* be 'Ignition Per Cylinder Comp'. You can see both, here:


Not knowing how this toggle or table was going to react, I started with the .68l tune where I pulled 4°. I wanted to make a pretty drastic change to 1 or 2 cylinders so we could definitively say it was or wasn't working. But, I set up three tunes:

.68l_-4 - No changes from prior
.68l_-4_IC - This only had the toggle checked, no other changes made
.68l_-4_IC_3-4_-4 - This used a value of -4° in cylinders 3 and 4 of the table

This is what Load/Ignition Advance/AFR curves look like for the three tunes:

^^We can already see something is happening in the tune where I changed cylinders 3 and 4

From before, this is what 1.10_.68l_-4 looked like for EGT's:


This is what the EGT's look like when you check the toggle in ATR (no other changes)


And this is what it looks like when I pulled 4° from both cylinders 3 and 4:

^^Quite the difference, eh?

Another way of looking at this is with the ΔT between cylinder 1 and cylinders 3 & 4 for each run:



By cylinder ignition comp works The AP does NOT like to log that...but I wonder if there's a way to log individual cylinder spark advance.

Subjectively: With 4° timing pulled on cylinders 3 and 4, it doesn't feel quite as smooth up to ~4,500 rpm, but after that it smooths out and even sounds smoother. I'll have to do more testing to see what actually happens to power production (the roads I used for this aren't perfectly flat, so VD isn't helpful).

I didn't grab a log or screenshot of it (will some other time), but this also affects cruising and idle EGT's similarly. With 4° pulled in cylinders 3 and 4, it brought the normal operating temps much closer together. So, it's also working in closed loop.

[Boosted Beluga]

Very interesting. Does it feel smoother?

[Lex]

Excellent results.

The lack of smoothness at lower RPM indicates to me that you are actually able to feel the difference in torque as the engine is going through the firing order 1-3-4-2. So there will be less torque made at 3-4 and you feel that until the power strokes happen at a high enough frequency to dampen the individual cylinder pulses.

If you lowered 1 and 4 or 3 and 2 you will feel less low RPM roughness but that's not the point.

While the EGT data has equalized the fact that you are feeling the difference in torque indicates that this is probably not the best approach to eliminating a possible imbalance.

I say a possible imbalance because we have quite a few variables to still consider:

- Is there a per cylinder fueling compensation? I will be looking into this shortly.
- Is the EGT imbalance due to the intake manifold flow?

The old MAPperformance numbers are this for the stock IM. According to these numbers Cylinder 3 and 2 should be hottest and 1 and 4 coolest.
# 1 = 218 CFM
# 2 = 258 CFM
# 3 = 273 CFM
# 4 = 227 CFM

- Is it due to the exhaust manifold design?

There is a missing link here somewhere. I don't see the correlation between EGTs and the problem cylinder 3.

[ms3blackmica]

Clint you are the man.

[Fobio]

Thanks for the testing, and doing exactly what you said you were going to do!

[snailD]

So glad someone is getting to the bottom of this, or at least scratching the surface! The people on this forum continue to amaze me, and im glad i'm around to soak up the information

[rtabagaboy]

Contradicting to what we are doing on the exhaust side could you put multiple MAF sensors in the intake manifold to so what each runner is flowing? Also, what cylinders get EGR? Would that effect anything and do you have the EGR delete?

Also to note; retarding timing increases EGT, but it also decreases cylinder temperatures. Could it be that Cylinder temps in 3&4 are higher ... essentially absorbing more of the combustion heat and less heat is going into the manifold.

[chuckms6]

Originally Posted by Lex Excellent results. The lack of smoothness at lower RPM indicates to me that you are actually able to feel the difference in torque as the engine is going through the firing order 1-3-4-2. So there will be less torque made at 3-4 and you feel that until the power strokes happen at a high enough frequency to dampen the individual cylinder pulses. If you lowered 1 and 4 or 3 and 2 you will feel less low RPM roughness but that's not the point. While the EGT data has equalized the fact that you are feeling the difference in torque indicates that this is probably not the best approach to eliminating a possible imbalance. I say a possible imbalance because we have quite a few variables to still consider: - Is there a per cylinder fueling compensation? I will be looking into this shortly. - Is the EGT imbalance due to the intake manifold flow? The old MAPperformance numbers are this for the stock IM. According to these numbers Cylinder 3 and 2 should be hottest and 1 and 4 coolest. # 1 = 218 CFM # 2 = 258 CFM # 3 = 273 CFM # 4 = 227 CFM - Is it due to the exhaust manifold design? There is a missing link here somewhere. I don't see the correlation between EGTs and the problem cylinder 3.

My argument is that by equalizing egt with per cylinder compensation, you are able to raise timing higher than otherwise since you won't be knock limited by the higher flowing cylinders running lean. The engine would run better as a whole and perhaps produce more power after setting per cylinder comp and adding timing as usual.

Naturally this is the only way to achieve that form of tuning however.

Sent from my SAMSUNG-SGH-I727

[Mfinlay04]

Originally Posted by chuckms6 My argument is that by equalizing egt with per cylinder compensation, you are able to raise timing higher than otherwise since you won't be knock limited by the higher flowing cylinders running lean. The engine would run better as a whole and perhaps produce more power after setting per cylinder comp and adding timing as usual. Naturally this is the only way to achieve that form of tuning however. Sent from my SAMSUNG-SGH-I727

Interesting, since we have no way of knowing exactly which cylinder is knocking. Maybe @phate; can do some runs on just gas and find a timing that causes a consistent low level knock and see if the ignition comp can pull the knock out of that cylinder. Doubt anyone wants to subject their motor to this kinda abuse.

Sent from my Galaxy Nexus using Tapatalk 2

[86AmishMs3]

Originally Posted by silvapain I have ported my IM and can trade you for your stock one for testing. Testing different EMs would require drilling and tapping four holes in each EM for the EGT thermocouples. I doubt many people would want that done to their manifolds.

I would like to see a ported stock manifold up there since a lot of us use it and try to remove the flow imbalances.

[Mfinlay04]

Does this thread makes anyone else want to go home and pull 4* from cylinder 3&4 yet??

Sent from my Galaxy Nexus using Tapatalk 2

[Spectrix]

Originally Posted by Lex The old MAPperformance numbers are this for the stock IM. According to these numbers Cylinder 3 and 2 should be hottest and 1 and 4 coolest. # 1 = 218 CFM # 2 = 258 CFM # 3 = 273 CFM # 4 = 227 CFM - Is it due to the exhaust manifold design? There is a missing link here somewhere. I don't see the correlation between EGTs and the problem cylinder 3.

I agree with Lex here, there is a missing link somewhere. We know that IM runner 3 flows the most and that IM runner 1 flows the least.
I would have thought that subsequently Cyl 3 would be the hottest (lean) and Cyl 1 the coolest (rich)


@Lex; has mentioned these possible variables

-Exhaust manifold flow imbalance
-Per cylinder ignition compensation (and at least we know this is possible now!)
-Per cylinder fueling compensation?


Other variables that might be worth considering -


-Flow balance within the head (Lets assume the manifold runner CFM numbers above were taken on a bench without a head)

-Compression ratio of each Cylinder
AFAIK Clint's build is 12:1 if I remember correctly @phate;?) Higher compression is said to = lower EGT (within reason)\
Have you done a recent compression test?

-EGT probe wires.. did you double check the probe runner numbers (without meaning any sort of disrespect! sorry!)


The only other thing I can think of is that the worst flowing cylinder (1) suffers incomplete combustion.

[Tokay444]

Originally Posted by Haltech When I worked for Acura, I was told that for every 5* of timing added over the base timing, expect your EGTs to increase 100F. Long before wideband use, we used EGT probes and gas analyzers to determine lean conditions with gen1 Legends with the V6 as they had some fueling issues. Keep in mind this is port injection, so I would expect cooler cylinder temps in direct inject engines. I appreciate Clint doing this EGT testing.. We always assumed cyl 1 was the leanest but now we can confirm it.

Egt's decrease with added ignition timing, as highlighted in Clint's experiment.
Combustion chamber temps will increase, but more fuel burnt in the chamber and less burning in the exhaust stream means cooler exhaust gasses.
And I think it was 3 that we all assumed would be leanest according to map's flow bench test of the stock mani. That brings me to a question. Has anyone else confirmed those flow bench numbers, or are we taking map's numbers as gospel?

[superskaterxes]

great results clint!!!


im really glad im not the only one ACTUALLY testing shit like this instead of just theorizing on the interwebs. Here are some of my thoughts so far:


Cyl 1 has the MOST RESTRICTION and cyl 3 has the LEAST RESTRICTION when looking at the IM flow numbers. Ultimately VE affects EGT's more then anything else. when you have a higher VE like in cyl 3 its going to burn more completely and therefore the EGT's will be lower. Cyl 1 is the farthest from the TB and farthest from the turbine inlet so it has the longest path. This combined with some seriously low flow numbers just means that cyl has to work extra hard for a complete burn compared to cyl 3.


some things i would like to see tested next:

- just like you subtracted 4 deg from cyl 3 and 4, you should now go back and add 4 deg to cyl 1 and 2 and see if you can achieve the same results.
- without changing anything tune wise from where you started the experiment, switch to a ported stock IM and then a JMF manifold to see how much the IM affects the EGT's vs the exhaust manifold design.
- Whichever of the 3 intake manifolds shows the most even EGT's (stock/ported/JMF) i would keep that on the car and then switch to a tubular exhaust manifold with equal length runners and see what happens.


the most equally flowing exhaust and IM combination should give you the most equal results because VE is the same for each cylinder.


like i said earlier, without people doing this type of research, this platform would still be stuck in the 400's.

[Ziggo]

This has nothing to do with incomplete combustion. Unless you are assuming cylinder 3 is running outside of the 10-14 AFR range there is test data set right here in this thread that shows that the leaner you run the higher EGTs get and yet cylinder 3 runs the cooler indicating the richest AFR, or the least amount of air. There are only two answers to this, either there is a by cylinder fueling compensation in the ECU, or when mates to the stock head with the stock log style exhaust manifold, there is not the significant flow imbalance that you would expect to see if you are just looking at the flow bench numbers.

[Spectrix]

Originally Posted by Tokay444 Egt's decrease with added ignition timing, as highlighted in Clint's experiment. Combustion chamber temps will increase, but more fuel burnt in the chamber and less burning in the exhaust stream means cooler exhaust gasses. And I think it was 3 that we all assumed would be leanest according to map's flow bench test of the stock mani. That brings me to a question. Has anyone else confirmed those flow bench numbers, or are we taking map's numbers as gospel?

I've only ever seen the one set of IM flow bench numbers from MAP. Certainly it's possible that another bench test might come out differently, but then those numbers are at least consistent with some better documented evidence such as runner 1 having a huge lump of alloy blocking it, and Cyl 3 being prone to failure.

[El_Diablo]

The only way to see a true imbalance that may be present is to flow the intake, head and exhaust manifold to see if possibly the exhaust manifold or head balance out the intake. Once we know these variables we can make solid conclusions but until then all we can do is make somewhat informed guesses.

[Lex]

Originally Posted by Ziggo This has nothing to do with incomplete combustion. Unless you are assuming cylinder 3 is running outside of the 10-14 AFR range there is test data set right here in this thread that shows that the leaner you run the higher EGTs get and yet cylinder 3 runs the cooler indicating the richest AFR, or the least amount of air. There are only two answers to this, either there is a by cylinder fueling compensation in the ECU, or when mates to the stock head with the stock log style exhaust manifold, there is not the significant flow imbalance that you would expect to see if you are just looking at the flow bench numbers.

How do you feel about the EGT probe location with respect to the collector and exhaust manifold runner length and path difference affecting the EGT readings and throwing an uncontrolled variable in the mix?

[phate]

I'm only going to hit on a couple points right now (gotta do work, lol).

Originally Posted by Mfinlay04 Interesting, since we have no way of knowing exactly which cylinder is knocking. Maybe phate can do some runs on just gas and find a timing that causes a consistent low level knock and see if the ignition comp can pull the knock out of that cylinder. Doubt anyone wants to subject their motor to this kinda abuse. Sent from my Galaxy Nexus using Tapatalk 2

I'm not sure how easily we'll be able to see actual knock. There should be a very brief drop in egt's when knock occurs (hopefully there's enough logging resolution), but with the ecu adding fuel and pulling timing, they'll shoot up right after.

Originally Posted by 86azms3 I would like to see a ported stock manifold up there since a lot of us use it and try to remove the flow imbalances.

That is probably the next step on my end.

Originally Posted by Mfinlay04 Does this thread makes anyone else want to go home and pull 4* from cylinder 3&4 yet?? Sent from my Galaxy Nexus using Tapatalk 2

I would definitely not do this. Like Lex said, the engine is probably making different power in those two cylinders, making it run rough. Tuning ignition advance to equalize egt seems like the wrong direction at this point.

Originally Posted by Spectrix -Compression ratio of each Cylinder AFAIK Clint's build is 12:1 if I remember correctly @phate;?) Higher compression is said to = lower EGT (within reason)\ Have you done a recent compression test? -EGT probe wires.. did you double check the probe runner numbers (without meaning any sort of disrespect! sorry!)

The last compression test I did was ~4,000 miles ago:

228-228-230-232 - but it is probably best to rule this out. [Car hasn't been running any differently, though].

Probe placement is a valid question, lol. I was careful when I hooked them up. The zeitronix probes have an extension that made it pretty easy. We do know, for sure, that probes C1 and C2 are at least in cylinders 1&2, and that probes C3 and C4 are in cylinders 3 and 4, just based on the ignition comp tests.

[Lex]

The by cylinder ignition advance is a cool feature and the OEM used it for the development of the engine but did not implement it in production. Just like the boost based toggle used for development initially.

[TiGraySpeed6]

Would it be worth the effort to repeat these same tests on a stock engine?

another local, so swap over in the driveway
comparisons of stock compression against high compression


Mostly to see data from a stock block with some mileage on it vs a new high compression set up that most of us will never have...

[Ziggo]

I have never heard much about it previously. Runner length will affect the actual temperature of the runner, but that shouldn't affect the temperature of the probe. The probe is a very small mass, located at the end of a long aspect ratio, making it as insulated as possible from the temperature of the actual manifold and very accurate and responsive at measuring the temperature of the gas

Now hotter runner equals hotter gas, but with the probes so close to the head, they are going to be catching the temperature of the combustion gasses at blow down without much of a chance to cool. When modeling motors we always treated the EGT temperature as the blow down temperature as far as thermodynamics was concerned, but that was with a basic Briggs twin and a equal length manifold and concentrating on learning about frictional losses. If you had individual probes located further down the runners I would be more inclined to believe that as a source of imbalance but I really don't know, we never accounted for it before and I don't have enough practical experience to say one way or the other.

More than those effects I am curious as to the compression results by cylinder and possibly playing a shell game with the coil packs. You can see how much of a difference timing makes, any extra triggering delay will have an impact. 2* of timing at 6k rpm is a difference of .05 milliseconds.

Zigatapatalka

[djuosnteisn]

Originally Posted by Lex Because exhaust enters the manifold in pulses, what you will generally find is that at a place where the pulses converge (ie the collector) you will see higher EGTs than in individual runners. This can be visually seen above. In diesels where EGTs are more strictly monitored they monitor EGTs either at the collector or right after the turbine. 3 and 4 clearly have shorter paths to the collector than 1 and 2 meaning that the probes themselves are closer to the collector. Further, longer runners have more mass to dissipate heat across before entering the collector than the shorter runner given that each exhaust pulse generates the same amount of heat energy and they are equally spaced in time (which they are). Yet ... 1 and 2 showed the highest temperatures consistently.

I have a feeling the flex bellows section may be causing a restriction, and thus heat backing up to cylinders 1 and 2 (just like they do in the collector in the pic you posted). For all we know, cyl 2's poor merge into the mani may even be pushing exhaust into cylinder 1. We know the firing order is 1-3-4-2, so since cylinder 1 fired well before cyl 2, it may result in a lower pressure pulse in that portion of the mani, enticing cyl 2's pulse to bleed over some.

Originally Posted by phate Part 2 - Ignition Timing Changes For every 2° of timing pulled, we increase EGT's by ~50°F (that's 25°F/1° timing, for the dense, lol) Part 3 - By-Cylinder Ignition Compensation Testing ... By cylinder ignition comp works The AP does NOT like to log that...but I wonder if there's a way to log individual cylinder spark advance.

You rock so fucking much Clint. Thanks a ton for doing this testing. I was always scared to mess with the individual timing trims cause i wasn't sure if a -1 would retard a degree, or advance a degree. Very very good data.

Originally Posted by Lex I say a possible imbalance because we have quite a few variables to still consider: - Is there a per cylinder fueling compensation? I will be looking into this shortly. - Is the EGT imbalance due to the intake manifold flow? - Is it due to the exhaust manifold design?

I have a feeling it's going to be a combination of effects. We know earlier spark advance results in lower EGTs (more heat in the chamber, less in the exhaust). We also know that richer AFRs result in cooler EGTs.

What about VE and flame speed though? I would imagine cyl's 3 & 4 would have the highest VE, least amount of residual exhaust after the exhaust stroke, and best cylinder filling on the intake stroke.

Perhaps the same bottle neck in the stock exh manifold design that's causing a restriction and higher EGTs for 1 & 2 is also effectively slowing down the flame speed inside the chamber (residual exh will indeed slow combustion speed). And in comparison, for a given global spark advance, the faster flame speed in cyl's 3 & 4 results in lower EGTs, because more of that heat energy is absorbed by the chamber (just like increasing spark advance).


I think we should compare the cylinder EGTs at different load points, not just wot. If cyl's 1 & 2 are hotter while just cruising around without enough flow to really cause issues in the exhaust manifold, then perhaps there's something else going on. But if they are generally only hotter at higher flow rates... then the above theory may be a little more plausible.

Originally Posted by Mfinlay04 Does this thread makes anyone else want to go home and pull 4* from cylinder 3&4 yet?? Sent from my Galaxy Nexus using Tapatalk 2

Don't go do that quite yet.




This is my new favorite thread. Thanks again Clint!

[phate]

Originally Posted by djuosnteisn I think we should compare the cylinder EGTs at different load points, not just wot. If cyl's 1 & 2 are hotter while just cruising around without enough flow to really cause issues in the exhaust manifold, then perhaps there's something else going on. But if they are generally only hotter at higher flow rates... then the above theory may be a little more plausible.

All good points, Dustin. I'm glad you joined the thread

The ΔT ratio between the cylinders has been pretty constant at all loads, the most constant has been cylinder 3 running cooler. The screenshots below show some of this, but I can grab some actual logs. When I pulled 4° from cylinders 3 and 4, it brought the cylinder's temps closer together everywhere - including cruising. I didn't let it idle for an extended time, but I presume we would see similar readings there, too. I can grab some low load comparison data later this week.

Originally Posted by phate This is what the cold start looks like in graph form. Peak occurred ~20s after it fired: Here is the temp after ~18 minutes: I took it for a quick cruise. Here is the car completely warmed up, driving at 65mph with the cruise control on (had been on for a couple minutes to make sure everything was steady): Pretty exciting, eh? 1176-1120-1086-1136 °F

[phate]

Here's another little nugget of info (since no one wants to download my spreadsheets )

Full EGT logs with deceleration - this is where the injectors are shut off, and it's interesting how quickly the cylinders cool (and that cyl 1 cools the most and quickest):

.68l_-4



.68l_-4_IC_3-4_-4

[djuosnteisn]

Originally Posted by phate All good points, Dustin. I'm glad you joined the thread The ΔT ratio between the cylinders has been pretty constant at all loads, the most constant has been cylinder 3 running cooler. The screenshots below show some of this, but I can grab some actual logs. When I pulled 4° from cylinders 3 and 4, it brought the cylinder's temps closer together everywhere - including cruising. I didn't let it idle for an extended time, but I presume we would see similar readings there, too. I can grab some low load comparison data later this week.

Do these sensors require any special calibration?

[phate]

Originally Posted by djuosnteisn Do these sensors require any special calibration?

Not that I'm aware of.

Edit: I should add that the LogWorks software does allow for calibration of all sensors. I went with the standard cal, because the Zeitronix probes were supposed to be direct replacements/stand ins for the Innovate probes.

[Dimenus]

I don't have much to add other than to thank @phate; for this awesome research. This forum is a really really awesome resource for anyone who wants to learn, even if you have no gearhead background.

Cheers.

[Enki]

Originally Posted by djuosnteisn I have a feeling the flex bellows section may be causing a restriction...

I don't know if any of you guys have cut a stock mani in half, but the bellows section is just that outside part with a floating piece of tube in the middle of it presumably to decrease airflow impedance. I can provide pictures if anyone needs to see what I'm talking about.

[djuosnteisn]

Originally Posted by Enki I don't know if any of you guys have cut a stock mani in half, but the bellows section is just that outside part with a floating piece of tube in the middle of it presumably to decrease airflow impedance. I can provide pictures if anyone needs to see what I'm talking about.

Post em up. I have like 7 stock exh manis at my house, i can cut one up too if needed.

I also assumed it'd be somewhat smooth on the inside, not ribbed for the EGTs pleasure lol. But it would be nice to see the diameter of the floating piece and how well it lends itself to flow.

[Easter Bunny]

Originally Posted by phate Here's another little nugget of info (since no one wants to download my spreadsheets )

What makes you think that any of us would even understand the information? I am having enough trouble with the help of the explanations you are providing.

[Roddiy]

@phate;

First of all thanks so fucking much for all this info, this is some crazy good stuff, definetely why the platform keeps advancing.


I have a few points to make:


#1 : All of these are done on a 50/50 mix of E85 correct? I know it pains you to run without corn juice, but is there any way you could give us some numbers using 93 gas? I'm not sure how E85 could affect the discrepancies in the cylinders. My theory is that the DeltaT would be smaller using the 93 gas than E85.


#2 : I think skaters said this already, but some results after adding 4* of timing to cylinders 1 and 2 would be good as well, in theory that should drop their EGTs to match cyl. 3 and 4.


#3 : I know VD isn't crazy accurate, but it could provide some insight with the whole pulling/adding timing per cylinder, anyways more data is always beneficial.





Again, you're a motherfucking G!